A plurality of devices communicating with one another may individually include driver circuits used for transmitting and receiving signals. A type of full-duplex communication uses a cable, such as a coaxial cable, whose number of cores (the number of signal lines) is small, for connecting the plurality of devices to one another. This type of full-duplex communication is described, for example, in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2005-514857.